Leuco-esters of n-dihydro-1:2-2&#39;:1&#39;-anthraquinone azines



Patented Dec. 9, 1941 lands3 f 1 N.332,102'. InGermany' May 15; 1939 9Claims.' mensen oponerse-trios "330579 'isf described anianufc'tureofleuco este f bythe" action of ametabnzoicacid sulphohalidthere" is Vobtained as the niai'n' 4product'acornpollnd vvhl'cliissluble inlwat 0t Varecl-lbro'vvfr The said Britishspecification.

It might have beenexpected that benzoic acid disulphochloride would*`yield an esterfication product more readilygsluble in water than theproduct ofExample 2 of saidlspecificaton.V If,

ducfionr'st'gwithidihyuroiidanthrn it should like'xvise have Aa'violetcolor.

'rho following is known of thsonnes"of'uiek acid L silllphuric'` estersofv leucoind'athrene: 'Ihle're eistV twc types" o f enel-esters" whichdiffer considerablywffron one another.` ,i

I. Disulphuricacid esters. ci jleucogN-dihydro'- 1 :2-2'1dianthraquinone 'azine sodium salt OSOaNa The disulphuric acid ester ofleuco-N-dihydro- 1:22':1anthraquinone azine in the form of its alkalisalts is sparingly soluble in water to a violet solution. The violetproducts referred to in the aforesaid specication correspond with the dfsoluble in water 1I.v Ttrasiuphurfo' acid esters of tobrahydor ester oacid. disulphochloride corresponds" lWi'tithe tetrafsulpliricfacidjesteri- -It is likewiseeiitrernely 40 the" itypi'cai grenuor'sceoeminatinof theratio'fof -dyestuf'fto sulphur that this easily solublecompound is in fact derived from tetrahydroindanthrene, that is to sayit contains four esteried enol groups. Consequently in the process ofthe present invention the acylation must be accompanied by a reduction.Such a course of reaction, proceeding by way of several intermediatestages, could not be sulphuric acid esters. The ratio of dyestuff to o5foreseen.

readily@ soluble l 1n Water`- and its solutions 'shovv It was asc'er''taiedla spectroscopic cmpa'rison 'that' -thenew ester hasthe'sairiespect-rum" asfthes tetrasul phur'ic7J acid fester oftetrahydroindanthrene; in` each case the absorption was found to be at'AThe new compound can be split by the action of alkalies with theformation of a vat and is a valuable product in dyeing and printing.

The reaction in accordance with the invention proceeds fairly smoothlyin the presence of py- 5 ridine. If instead of pyridine a homologuethereof, such as picoline, or another tertiary base is used, there areobtained in larger quantities products yielding violet solutions inaddition to the product yielding a fluorescent solution.

The following example illustrates the invention, the parts being byweight:

40 parts of benzoic-acid-3g-disulphochloride are introduced into 240parts of dry pyridine. To the addition compound of pyridine with the l5acid chloride thus obtained are added parts of the dry leuco compound ofN-dihydro- 1:2-2:1anthraquinone azine (prepared by'reducing with causticsoda solution and hydrosulphite, acidifying the blue vat and drying the20 product under reduced pressure in an atmosphere of carbondioxidewithout use of a solvent). The mixture is heated for 1 hour at 70 C. ina current of dry nitrogen. The reaction mixtureis then poured intowater; and the whole is dis- V tilled under reduced pressure until freefrom pyridine and at the same time strongly concentrated. Any sparinglysoluble violet di-ester and unchanged indanthrene which may be presentare separated by ltrationand the red-brown ltrate is concentrated tothe'consistency of a paste. The ester salt can be precipitated by theaddition of potassium chloride and much alcohol. By gently heating theiiuorescent solution of the product with sodium carbonate theiiuorescence is destroyed and a violet solution is obtained.

From this solution it is possible to isolate by salting out a body whichanalysis shows to be a leucoindanthrene ester in which no longer four 49but only two enol groups are esteried with benzoic acid -disulphonicacid, so that partial saponication has taken place.

If the fluorescent solution is heated for a longer time with sodiumcarbonate or if it is treated with caustic soda solution, the product isYcompletely saponified with the regeneration of the parent dyestuif.

lThe leuco compounds of 3:3'-dichloro-N dihydro-1:2-2:1'anthraquinoneazine, of 3:3'- 50 dibromo N dihydro 1:2-2 :1'- anthraquinone azine orof N-dihydro-1z2-2:1'anthraquinone azine -3:3dicarboxylic acid yieldunder the conditions above described products which are liked wiseeasily soluble in water to brown to reddish- 5 brown solutions having agreen fluorescence.

What I claim is: Y

1. A process for thermanufacture of easily water soluble leuco-esters ofN-dihydro-1:22':1' anthraqunone azine dyestuffs, comprising caus-` 69ing the leuco compound of a Ndihydro-1:22':1 anthraquinone azine toreact with a benzoic acid disulphohalide in the presence of a pyridinebase.

2.'A process for the manufacture of easily o Water soluble leuco-estersof Ndihydro-1:22:1'

anthraquinone azine dyestuils, comprising causing the leuco compound ofN-dihydro-1z2-2'z1'- anthraquinone azine to react with a benzoic aciddisulphohalide in the presence of a pyridine base.

3. A process for the manufacture of easily water soluble leuco-esters ofN-dihydro-l :2-2' 1'- anthraquinone azine dyestuffs, comprisingcaushydro-1:2-2:1'anthraquinone azine to` react with a benzoicdisulphohalide in the presence of a pyridine base.

4. A process for the manufacture of easily water soluble leuco-esters ofNdihydro-1:22' 1 anthraquinone azine dyestuffs, comprising causing theleuco compound of a Ndihydro-1:22':1 anthraquinoneazine'to react with abenzoic acid disulphochloride in the presence of a pyridine base. 4

5. A process for the manufacture `of .easily water soluble leuco-estersof N-dihydro1:22' 1'- anthraquinone azine dyestuffs, comprising causingthe leuco compound of a N-dihydro-1:22:1 anthraquinone azine to reactwith a benzoic acid disulphohalide in the presence of pyridine.

6. Avprocess for the manufacture of an easily Water soluble leuco-esterof N-dihydro-lzZ-Zrl'- anthraquinone azine, comprising causing the leucocompound of N-dihydro-1z2-2: 1anthra-LV quinone azine to react with abenzoic acid disulphochloride in the presencey of pyridine. e

7. A process for the manufacture of an easily water soluble leuco-esterof 3:3'dichloro-Ndi hydro-1; 2-2' lanthraquinone azine', comprisingcausing the leuco compound of 3:3di` chloro-N-dihydro-l 2-2:v1anthraquinone azine to react withja benzoic acid disulphochloride inthe presence of pyridine.

8. As new articles of manufacture easily water soluble leuco-esters ofN--dihydro-1z2-2z1'- anthraquinone azines, Ywherein the hydrogen atomsof the four enolic hydroxy groups are substituted by the radical SQaHsaid esters giving brown to red-brown watery,

solutions with intense green fluorescence and yielding when warmed inthe presence of alkali said ester giving a red-brown watery solutionwith intense green fluorescence an-d yielding when warmed in thepresence of alkali the parent KARL GLENZ.

